A good number of our stores sell > $1M/month. And, now that Shopify 2 has shipped, any feature gaps that were around are closing very quickly.
Order creation will be open soon.
Every e-commerce product across-the-board has this feature, and it's disappointing to see a platform as well-crafted and mature as Shopify still without many of the essentials.
We can now officially create orders via a POS system, but still can't create an order on our own website without registering as a customer or jumping through 3rd party shipping/tax/payment APIs.
There's no API order creation at present, but the API is consistently evolving as the platform does.